Original
In the case of a genuine oil filter, the product name, part number, logo and other wording are finely printed yet clearly identifiable. The plastic interior is precisely manufactured and, when mounted, the filter offers a perfect fit.

Forgery
The wording is coarser, often indistinct or missing completely. The fake filter is shorter than the original and the gasket is of appreciably inferior quality. The interior uses cheap wire and poor-quality adhesive.